John Tan

Safety of food challenges to extensively heated egg in egg-allergic children: a prospective cohort study

Many children with IgE‐mediated allergy to egg can tolerate egg in baked foods. However, the clinical characteristics and severity of reactions of egg‐allergic children who react to baked egg at open food challenge (OFC) are not well defined.

A randomized trial of egg introduction from 4 months of age in infants at risk for egg allergy

Background: Epidemiologic evidence suggests delayed introduction of egg might not protect against egg allergy in infants at risk of allergic disease. Objective: We sought to assess whether dietary introduction of egg between 4 and 6 months in infants at risk of allergy would reduce sensitization to egg. Methods: We conducted a randomized controlled trial in infants with at least 1 first‐degree relative with allergic disease. Infants with a skin prick test (SPT) response to egg white (EW) of less than 2 mm were randomized at age 4 months to receive whole‐egg powder or placebo (rice powder) until 8 months of age, with all other dietary egg excluded. Diets were liberalized at 8 months in both groups. The primary outcome was an EW SPT response of 3 mm or greater at age 12 months. Results: Three hundred nineteen infants were randomized: 165 to egg and 154 to placebo. Fourteen infants reacted to egg within 1 week of introduction (despite an EW SPT response <2 mm at entry) and were unsuitable for intervention. Two hundred fifty‐four (83%) infants were assessed at 12 months of age. Loss to follow‐up was similar between groups. Sensitization to EW at 12 months was 20% and 11% in infants randomized to placebo and egg, respectively (odds ratio, 0.46; 95% CI, 0.22–0.95; P = .03, χ2 test). The absolute risk reduction was 9.8% (95% CI, 8.2% to 18.9%), with a number needed to treat of 11 (95% CI, 6–122). Levels of IgG4 to egg proteins and IgG4/IgE ratios were higher in those randomized to egg (P < .0001 for each) at 12 months. There was no effect on the proportion of children with probable egg allergy (placebo, 13; egg, 8). Conclusions: Introduction of whole‐egg powder into the diets of high‐risk infants reduced sensitization to EW and induced egg‐specific IgG4 levels. However, 8.5% of infants randomized to egg were not amenable to this primary prevention.

Baked egg food challenges – clinical utility of skin test to baked egg and ovomucoid in children with egg allergy

Many children with IgE‐mediated egg allergy can tolerate products containing extensively heated (baked) egg. Aside from food challenge, there are no tests which reliably predict tolerance to baked egg in egg‐allergic individuals.

Egg allergy: An update

Egg allergy is the commonest infant food allergy both in Australia and world‐wide. The clinical presentation of egg allergy is varied – egg is involved in both IgE and non‐IgE‐mediated allergic reactions and has been implicated in conditions such as anaphylaxis, food protein‐induced enterocolitis syndrome, atopic dermatitis and eosinophilic oesophagitis. The clinical presentation, pathophysiology and diagnosis as well as the natural history and management of egg allergy will be discussed. Current theories about primary prevention as well as potential future therapies are presented. Finally, practical information about egg allergy and immunisation is provided.

Insect allergy in children

Allergic reactions to insect bites and stings are common, and the severity of reactions range from local reaction to anaphylaxis. In children, large local reaction to bites and stings is the most common presentation. Stings from insects of the order Hymenoptera (bees, wasps and ants) are the most common cause of insect anaphylaxis; however, the proportion of insect allergic children who develop anaphylaxis to an insect sting is lower than that of insect allergic adults. History is most important in diagnosing anaphylaxis, as laboratory tests can be unreliable. Venom immunotherapy is effective, where suitable allergen extract is available, but is only warranted in children with systemic reactions to insect venom. Large local reactions are at low risk of progression to anaphylaxis on subsequent stings, and hence, venom immunotherapy is not necessary.

ANAPHYLAXIS TO AN ONDANSETRON WAFER

1 Bandyopadhyay D, Ghosh SK. Mucocutaneous features of Chickungunya fever. Int. J. Dermatol. 2008; 47: 1148–52. 2 Haas H, Robin S, Ramful D et al. Chickungunya virus infections in children. Arch. Pediatr. 2009; 16: 72–9. 3 Inamadar AC, Palit A, Sampagavi VV et al. Cutaneous manifestations of Chickungunya fever. Int. J. Dermatol. 2008; 47: 154–9. 4 Riyaz N, Riyaz A, Rahima et al. Cutaneous manifestations of Chickungunya during a recent epidemic in Calicut, North Kerala, South India. Indian J. Dermatol. 2010; 766: 671–6. 28 February 2011 Dear Editor,

Striking the balance between primary prevention of allergic disease and optimal infant growth and nutrition

The timing of introduction of solids and/or complementary feeds continues to be an area of intense interest with respect to allergy prevention and general optimal infant nutrition. There is recent evidence from RCTs (1-3) and a meta-analysis(1), that the earlier introduction of peanut (between 4 and 11 months) and egg (between 4 and 6 months), in infants at higher risk of allergic disease, may be beneficial. However, concerns have been raised over the impact this may have on duration of breastfeeding, nutrition and growth, when a high protein and calorie-containing food, such as egg or peanut, is introduced. Duration of breast feeding appears to have little impact on development of allergic disease, but is important for protection against overweight and obesity, diabetes and childhood infections (particularly in resource poor settings)(4). This article is protected by copyright. All rights reserved.